How do we do this? Here are four effective course of action that will definitely help.
Self
Look deep inside you. Dissect your heart. For everything that you do and say comes from the heart. It is what you are that dictates your relationship with others. Seek first to understand then to be understood.
“I know that good does not live in me - that is, in my human nature. For even though the desire to do good is in me, I am not able to do it.” (Romans 7:18)
Forgive That You May Be Forgiven
Harboring a grudge for a wrong done to you is defined as a feeling of resentment and a synonym with bitterness. Bitterness if not released will have a devastating health effect; it's not good for the heart, mind and spirit. Forgiveness is its only proven antidote.
“If your brother sins against you go to him and show him his fault. But do it privately, just between yourselves. If he listens to you, you have won your brother back.” (Matthew 18:15)
Apologize
It's difficult and sometimes awkward to make the first move. It takes humility and grace of the spirit. But it's the first step to heal a feud, a misunderstanding of broken hearts. Initiate the first move. Say sorry if you were at fault.
A genuine apology shows respect and leads to reconciliation. Don't let pride get in the way. You'll feel good afterward and sleep better.
“If he sins against you seven times a day, and… returns to you, saying, “I repent,” you shall forgive him. (Luke 17:4)
Restitution
Restitution can be done little by little. It just takes patience and commitment to show your genuineness and wholehearted intention. But the reward will be worthwhile.

“Love is patient and kind; it is not jealous or conceited or proud,
Love is not ill-mannered or selfish or irritable,
Love does not keep a record of wrongs,
Love is not happy with evil, but is happy with the truth.
Love never gives up; and its faith, hope and patience never fail.”
(1Corinthians 13:4-7)